1. Field of the Invention
The present invention is directed to a microscope, in particular an optical scanning microscope with illumination of a specimen via a beam splitter
2. Related Art
In U.S. Pat. No. 6,888,148 among other things a beam splitter is described for a line scanner.
In a line scanner the specimen is illuminated with a line focus (e.g. along the X-coordinate), which is shifted in the coordinate (Y) perpendicular to the line. For this the source of light is linearly focused into an intermediate image plane of the microscope mechanism by means of optics. By the focusing in Y direction in the intermediate image, for example by a cylinder lens, a linear and diffraction-limited distribution of intensity arises along X on the specimen. With further optics the light is focused into the pupil of the microscope arrangement. In the pupil levels of the microscope arrangement a line focus results in each case. The pupil levels and the scanner are conjugate to each other and to the rear focal plane of the microscope arrangement, so that the scanner can induce the linear and diffraction-limited focused distribution of intensity perpendicular to this (Y-coordinate in the specimen). The focusing into the specimen is made by scan optics, the tube lens and the objective. Relay optics produces conjugate pupil levels of the microscope arrangement. Due to the kind of the specimen reciprocal effect e.g. during an excitation for fluorescence or luminescence the light emitted from the specimen is of small spatial coherency. That is each point excited in the specimen radiates essentially independently of the neighboring points as point emitter into all directions in space. The optics, (e.g. a microscope objective) displays the individual point emitters together with the tube lens TL into an intermediate image plane ZB of the microscope mechanism, whereby the pupil P is illuminated homogeneously (broken light path) by wave fronts that are essentially incoherent to each other and of different directions of propagation. In the pupil is the element which separates the excitation light from the detection light.